Unfortunately nonfunctional

First was pleasantly surprised by the device.
Beautiful appearance, good handling (press), very good display,
But ....
Said noise (if backlight on) is disturbing and could trigger deserves 2 stars.
However, my device was not functional. When a telephone conversation is always just loud noise to understand (have Ip connection). Outgoing phone calls worked perfectly.
Phone Software Update performed -> without success, routers update -> without success. HD telephony in the router is turned off, without success.
Moreover, it was also the battery after a short time empty (as previously described by others)
Another shortcoming: handset volume is not changed

Too bad, because otherwise would be a nice, simple device.